1. Field of the Invention
This invention relates to the beads of those tires which rest radially of the inside of the wheel rim, called hooked tires.
2. Related Art
Wheel rims designed to receive such tires comprise on each side a seat, usually inclined slightly relative to the axis of the wheel rim. The seat is extended axially outward by a flange which projects approximately perpendicular to the axis and extends radially inside the wheel rim. To assure a correct positioning of the tire on the wheel rim, guaranteeing good static and dynamic balancing, the tire should rest uniformly on the seat as well as against the flange. In other words, the pressure of wheel rim-tire contact should be circumferentially constant.
The bead of tires with reverse beads generally comprises a large volume of rubber, which results in a great variation in the positioning of the bead wire. If the effect of the variations caused by the manufacturing tolerances of the wheel rims and bead wires, as well as the molding tolerances of the bead, are added to this, the result is that in mounting position the ratio of the thickness of rubber between the bead wire and the face of the bead that is intended to rest on the wheel rim divided by the ideal spacing between the bead wire and the surface of the wheel rim varies significantly. Since this ratio determines the tightness of the bead on the wheel rim, such variations of this ratio very often cause the tightness variations to exceed acceptable tolerances.
Therefore, it cannot be guaranteed that the tightness will be adequate. Consequently, the bead wire is positioned off center relative to the wheel rim and/or is not placed in a plane manner, and/or is placed in a way not parallel to the flange.
If an adjustment of the bead wire which guarantees the existence of an adequate tightness is chosen, then considering the large variations of this tightness, the adjustment will be such that tightness is in some cases so great that it will not be possible to mount certain tires.